Hi All,

I totally agree with Robert on his information regarding periodic acid and chromic acid. I have done extensive research on this subject when I developed my special stain kits for Biocare Medical.  I did incorporate 10% chromic acid for the GMS stain, and 1% periodic acid for the PAS stain. 

As far as this forum for political views,  in frustration, I deleted everything with these headings.  There could of been some very interesting feed-back, but you have used this source totally inappropriately!  I believe in this countries beliefs for freedom of speech, but use it wisely!!  The histonet is NOT THE PLACE! 

Akemi Allison-Tacha, BS, HT(ASCP)HTL
Client Services Manager
PhenoPath laboratories
551 North 34th Street, Suite 100 
Seattle, WA 98103-8675
Work: (206) 374-9000 ext 1053
E-Mail: akemiat3377@yahoo.com


--- On Wed, 11/5/08, Robert Richmond  wrote:

> From: Robert Richmond 
> Subject: [Histonet] Re: Fungal stains
> To: histonet@lists.utsouthwestern.edu
> Date: Wednesday, November 5, 2008, 7:29 PM
> Colin Weaver asks about staining of various fungal species
> by the
> standard fungal stains.
> 
> The standard fungal stains have two basic steps:
> 
> 1. Periodic acid or chromic acid splits bonds between
> vicinal diol
> groups (two carbons with OH"s on adjacent carbon
> atoms) and oxidizes
> the free ends to aldehyde groups (-CHO).
> 
> 2. The aldehyde groups oxidize Schiff's reagent or
> methenamine silver
> to produce a visible deposit.
> 
> Periodic acid is not a sufficiently strong oxidant to
> demonstrate some
> fungal cell walls. In human pathology, Histoplasma is most
> likely to
> stain weakly or not at all. You need chromic acid, most
> usually
> followed by methenamine silver.
> 
> Unfortunately, many so-called GMS kits silently substitute
> periodic
> acid for the more hazardous chromic acid. Freida Carson
> reviewed this
> top in J Histotechnol several years ago - I can find the
> reference if
> anyone needs it (I think I've posted it on Histonet
> before, so it's
> probably in the archives.) So your first step is to see if
> you're
> actually using chromic acid.
> 
> PLEASE get the politics off this list - the repetitious
> garbage is
> making the list hard to read, particularly in digest form.
> Linda
> Margraf, if it doesn't stop, I suggest moderating the
> list for a few
> days, though not permanently.
> 
> Bob Richmond
> Samurai Pathologist
> Knoxville TN
> 
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